There are many techniques used for mounting an electronic component with a solder bump formed on an electrode on a substrate through thermal bonding. In these techniques, the electronic component is pressed against the substrate using a bonding tool and heated to melt the solder bump for solder bond onto an electrode of the substrate. In this thermal bonding process, continuous pressing after melting the solder bump can squash and deform the melted solder. To avoid deforming the solder bump, the position of the thermal bonding tool is fixed before melting the solder bump. However, even if the thermal bonding tool may be fixed, there is still deformation due to loading in a load cell for detecting a pressing force. Upon release of this residual deformation, the thermal bonding tool can move downward to squash and deform the melted solder bump.
There have hence been proposed techniques of bringing a thermal bonding tool to have a reduced pressing force before solder bump melting, using the thermal bonding tool to press an electronic component having a solder bump against a substrate, starting to heat the electronic component, and then if the pressing force becomes equal to or lower than a predetermined value, raising the thermal bonding tool based on the determination that the solder is melted (see Patent Documents 1 and 2, for example).
There has also been proposed a technique of, after starting to increase the temperature of an electronic component using a thermal bonding tool, bringing a head tool into constant control of a pressing force on the electronic component, detecting reduction in the loading measured using a load cell to determine that the solder is melted, and switching the operation of the head tool from the constant loading control to position control in which the height of a leading end of a suction nozzle is made positionally constant to reliably control the dorsal height of the electronic component even while the solder is melted (see Patent Document 3, for example).